In the field of solid-supported organic synthesis the physical separation of the support from the solubilized components of the reaction mixture has primarily been accomplished by filtration through a glass or polymer filter. Although filtration has been the method of choice in both solid-phase peptide and nucleotide synthesis it does have limitations that warrant the development of new approaches. One such limitation is the difficulty in automating the simultaneous washing and filtration of hundreds of small scale solid-phase reactions. A field that has had some success in translating some of its techniques into automation is immunodiagnostics. Exposing antibody-bound paramagnetic beads to a magnetic field can be used to separate antibody-bound antigen from unbound antigen in immunoassays..sup.1,2 Magnetic separation methods have also been applied successfully in cell sorting..sup.3-5 A definite advantage that magnetic separation has over simple filtration is the ability to separate out particles in small reaction volumes. The use of magnetic separation in the field of solid-supported organic chemistry has been slow in coming due to the instability exhibited by the currently available supports in organic solvents such as dimethylformamide and methylene chloride. Upon exposure to these solvents the typical polymer coated magnetic beads dissolve. Silica coated magnetic beads as well as high cross-linked polystyrene paramagnetic beads have become available which are more stable to these solvents and can withstand higher temperatures..sup.6
Equipment to mechanically separate out paramagnetic particles or beads is known..sup.7,8 Unfortunately, these apparati and methods are primarily aimed at solid phase biochemical reactions which are normally run at room temperature and in buffered water. The development of equipment to heat, agitate and magnetically separate paramagnetic particles in one integrated machine would be instrumental in facilitating the use of paramagnetic particles in solid-phase organic synthesis. Further, a means for enhancing the rate of reaction during organic synthesis to increase the efficiency is desirable.